The present invention relates to a dimensionally stable pressure sensitive label structure which provides label stock that is particularly useful in withstanding high temperature use applications, exemplary of which would be as in the circuit board industry where bar code labels are affixed to circuit boards to facilitate identification and real time data tracking during the assembly operations, which in the surface mount and through-hole assembly environments and technologies subject the labels to temperature environments in the 800-degree Fahrenheit area.
Prior to the instant invention, attempts to use conventional laminate structure bar code labels in high temperature processing environments resulted in the label face stock material, upon which the bar code imagry was printed, becoming dimensionally unstable and pliably distorting to the extent that the bar code imprinted thereon became illegible to sensors of compatable scanning equipment and thus the advantageous capabilities for facilitated component identification and real time data tracking of components during processing operations was defeated.
The base laminate structure of the label comprising the instant invention is old and well known in the art, what is new and novel, however, is that following printing and curing of either or both machine and human readable matter upon the unplasticized polyvinyl chloride face stock material component of the base laminate structure, an additional and thermally stable laminate ply comprised of high polymers which have an imide in the polymer chain, which is manufactured and commercially sold by the DuPont Corporation of Wilmington, Del., under the Tradename "Kapton", is mechanically bonded with a suitable interposed adhesive film to the imprint cured unplasticized polyvinyl chloride face stock, which thereby provides the necessary imprinted face stock material stability under use application in high temperature operational environments of up to 800-degrees Fahrenheit and thereby prevents deformation of the imprinted face stock material upon going to a pliable state in high temperature use, or distorting upon cooling, such that imprinted machine readable matter thereon remains 100% legible to compatable scanning equipment sensors before, during, and after use exposure of the dimensionally stable pressure sensitive label structure.